WonkyV, I have read your long post and I am well aware that readback errors occur. However, simply hammering the QNH in by repeating it
ad nauseam will not solve anything.
Originally Posted by
WonkyVectors
... Wow, are you seriously advocating that EVERY pilot get airborne without clarifying their altimeter setting?
No, I am not ... and if you care to read my previous posts (which it seems you may not have done) you will see that I am not suggesting that. Each pilot in a multi-crew environment will have taken the QNH from the ATIS and set it independently on his/her altimeter and, as part of normal procedure, confirmed that the airfield altitude is indicated, and that this reading is within altimeter tolerances. This should be done by each pilot independently and therefore represents two checks. Furthermore, the ATIS letter will also be read back to ensure that it contains current information at start-up - and that is then a third check.
Originally Posted by
WonkyVectors
... The simple fact is that I (controller) HAVE to, and WANT to, clarify that you (pilot) have the correct setting, and sorry, but "info Kilo" is not sufficient. ...
I understand but I still maintain that one check (the ATIS letter)
should be sufficient to do this for you. Reading back the QNH as well will make no difference to, say, a mis-set altimeter. Short of coming out to the cockpit to look at our altimeters to satisfy yourself that the subscales are correctly set, what else can you do? That is not your responsibility, it is ours. Simply blasting the problem by demanding another readback request is akin to saying "in case they don't understand, speak slower AND SHOUT!" It will not 1) protect against transposition errors when either setting or copying, nor 2) avoid (your example) a subsequent error by the mis-hearing or mis-setting of a cleared FL, nor 3) protect against (your further example) where an aircraft climbs on a SID to an altitude rather than a FL (or
vice versa), nor 4) prevent the setting of "Hg instead of Mb by our North American friends. All these are errors which of course need to be addressed in their own way, but I would suggest they are not fundamentally related to the topic we are discussing.
I could go on, but I won't. The examples you give are fair comment on human performance and I accept these things happen in practice. I have been a professional pilot since 1970 and I fully understand what you are saying. However, simply blasting the pilot with QNH on a repeated basis will not help to remedy any of the errors you have mentioned.
By the way, I have visited quite a few ATSUs in my time so I am very familiar with what you do and also what can happen on both sides, because ATCOs and pilots are both human - what you chaps do is generally admirable and the overall standard of ATC in UK is, in my view, the best.
However, I simply do not agree that this QNH double-speak is either helpful or an aid to safety. In my opinion, it would need evidence to show that a mis-set altimeter(s) before take-off prompted an incident (like an altitude bust),
and that it was caused solely or principally by a mis-set altimeter sub-scale ...
and that the mis-setting could have been avoided by a further repetition of the QNH to the pilot before take-off, in addition to acknowledging the ATIS correctly. Without such corroborative evidence, I'm afraid I remain highly sceptical that this is actually a benefit to safety and nothing in this thread has so far encouraged me to change my mind.
JD
